* build.conf
  (svn): The new 'svn auth' command links directly to serf, so add an explicit
   dependency here. Hopefully fix build failures on buildbots since r1572105.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1572116 13f79535-47bb-0310-9956-ffa450edef68